Charge forming device



Aug. i8, i931., F. E. ASELTINE ET AL CHARGE FORMING DEVICE Filed sept. 22j 1927 4 sheets-sheet 1 MVN VNN

ug, 18, 193i. F. E. ASELTINE ET AL,s

CHARGE FORMING. DEVICE Filed Sept. 22, 1927 4 Sheets-Sheet 2 gjywwtouz ff/m MM Aug. 18, 1931. F. E. AsELTmE ET AL CHARGE FORMING DEVICE 4 snets-sheet s Filed sept. 22. 1927 kskwm@ n www5 4 Sheets-Sheet 4 om, rw www QQ i @m No m@ H J www u H m A NN SSN m WNN Patented Aug. 1s, 1931 UNITED STATES FRED E. AmTINE AND WILFR-D H. TEETER, OF DAYTON, OHIO, ASSIGNORS, BY HERNE,

PATENT oFEicE ASSIGNMENTS, T0 DELCO PRODUCTS CORPORATION, OF DAYTON, OHIO, A COB- POBATION OF DELAWARE CHARGE ronMIivG DEVICE Application led September 22, 19587. Serial No. 221,371-

ors each located adjacent an engine 'intake' port and receiving fuel-air mixture from a ipe connected with one of the primary caruietors .and receiving air when required` through one branch of an air manifold which supplies airto all of thesecondary carburetors. The primary carburetors receive their liquid fuel from a common fuel bowl in which the level is controlled by a float valve.

' One example of a carburetor of the character lreferred to above is disclosed in the coending application of F. E. Aseltine, Serial 10. 83,979, filed January 26, 1926 which matured to patent 1,727,266 granted Sept. 3,'

1929. In the Aseltine carburetor admission of air to the air manifold is controlled by a spring loaded valve, and throttling of the engine is effected by separatethrottle valves located between the secondary mixing chambers and the engine intake ports, such valves being) controlled by a common operating mem er A second example of a carburetor f this.

nature is illustrated in the copending application of W. H. Teeter, Serial No. 221,372,

' led Sept. 22, 1927. In the Teeter carburetor a plurality of primary carburetors are provided, one for each intake port. The fuel mixture from such primary carburetors is conveyed to secondary mixing chambers located adjacent the various engine intake ports where it is mixed with additional air. In the Teeter device throttling of the engine is effected by a single primary throttle which controls all the primary carburetors, and a single main throttle controlling the air ilow through the main air manifold. These throttles are operated from a common operating mechanism which is so arranged that the primary throttle controls the quantity ofmixture passing to the engine at speeds up to'a vehicular speed` of 20-25 'miles per hour, after which the main air throttle begins to open. and becomes the main controlling element regulating the mixture outflow.

Various devices are provided in the Teeter carburetor above referred to for controlling the flow of fuel and air under various operating conditions so as to secure a mixture having the desired fuel and air ratio underA all conditions of operation.

i The general obJects of boththe charge forming devices above' referred to are first to provide a mixture of fuel-and air having the desired fuel and air ratio under all operating conditions, and todeliver equal quantities of this mixture to each cylinder of the engine under various conditions 'of load and speed, without requiring the heating of the fuel or fuel mixture before it is delivered to the engineintake; i i

The charge forming device formin the subject of the present invention is o the same general type as the Teeter carburetor above referred to, and the rincipal objectV of this invention is to provi e in such device improved mechanism for proportionin the fuel mixture and to improve and simplig the construction throughout.

The present invention accomplishes its general object by a construction which avoids the use of a separate throttle valve in each of the secondary carburetors and which permits -the use of a very simple form of secondary carburetor associated with each engine intake port. The presentinvention is embodied` in a charge forming device comprising an air manifold which does not include any of the control mechanism of the carburetor, and a. main carburetor unit adapted to be attached to and supported bv the air manifold, said unit including chiellya fuel bowl, the pri-l mary carburetors to which liquid fuel is distributed from the fuel bowl, and all of the' valves and control mechanism associated therewith for controlling the ow of. air through the air manifold and the flow of primary ifuel mixture from the primary carburetors to the secondary carburetors at each engine intake port. In the disclosed form of this invention, the primary mixture is conducted from each primary carburetor to each secondary carburetor through a pipe which is formed of separable sections, one section being attached to the main carburetor unit referred to and the other being attached as an insert to each branch of the air manifold. In this way the main carburetor unit may be readily attached to or detached from the air manifold, permitting the manufacture of the air manifold and the main carburetor as separate units.

In addition to securing these advantages, this invention aims to providethe proper fuel mixture for'all 'conditions of speed and load of the engine, and particularly such mixtures as are economical and those which will aid in the rapid acceleration of the engine under different conditions.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of embodiment of the present invention is clearly shown.

In the drawings:

Fig. 1 is a plan view of a form of the present invention shown in connection with an engine cylinder head block, portions of which are shown in horizontal section.

Figs. 2 and 3 are sectional views on the lines 2-2 and 3-3 respectively of Fig. 1. Fig. 4 is a side elevation of the device.

Fig. 5 is a sectionalview on the line 5-5 of Fig. 4.

Fig. 6 is a sectionaliview on the line 6 of Fig. 1.

y Fig. 7 is an end yiew looking in the direction of the arrow 7 in Fig. 4.

Fig. 8 is an end view looking in the direc-` tion of the arrow 8 in Fig. 4.

Fi 9 is a sectional view Von the line 9-9 of Fig. 8.

, 10m-10a of Fig. 7.

`the line --15 of Fig. 14.

Fig. 11 is a sectional .view on the line 11-11 of Fig. 1.

Fig. 12 is a sectional view on the line 12--12 of Fig. 11.

Fig. -13 is a sectional view on the line 1er-13 of Fig. 11.

Fig. 14 is a sectional view on the line 14--14 of Fig. 11.

Fig. 15 is an enlarged sectional view on Fig. 16 is a fragmentary sectional view on the line 16-16 of Fig. 11.

Fig. 17 is an enlarged vertical sectional view of the dashpot piston and piston rod, blow-off valve and check valve.

l Fig. 18 is an enlarged'vertical sectional view of an alternative form of multiple stage metering device controlling the ow of fuel from the float bowl to the distributing canal of the primary carburetors. y

Fig. 19 is a sectional view on the line 19--19 of Fig. 18.

Referring to the drawings, 20 designates an air manifold having an inlet at 21 (see Fig. 11) and having three` branch pipes 22 each connected with a cylinder head intake port 23. Each intake port 23 supplies fue] to a pair of engine cylinders through cylin-l der valve ports 23a and 236. In Fig. l, the cylinder head is shown in three separate fragments 24 but it will be understood that it may be an integral structure. The air manifold 20 is secured to the cylinder block 24 iny any suitable manner similar to that employed for attaching the conventional intake manifold to the cylinder head. Adjacent its intake, the manifold 20 is provided with an attaching liange 25 to which may bebolted the carburetor unit which will now be described. y l

The main .carburetor unit comprises a' housing 30, in the form of a single casting, which is attached to the flange 25 by screws 31. The housing 3() provides an air'chamber 32, the admission of air to which is controlled vided by an air horn 36. The member 36 is attached to the member by screws' 37.

` For convenience in manufacture the member closed by a plate 39. The bottom. wall 40 of the chamber 32 is provided with a large opening 41 to allow passage of air from the chamber 32 to a chamber 42 from which air is supplied to the primary carburetors to be described. The air chamber 32 is connected with the air manifold inlet 21 b a passage 43 controlled by an air thrott e valve 44 mounted on a shaft 45 which is supported as shown in Fig. 12 by the side walls of the member 30.

. Referring to Figs. 11 to 18 inclusive, there are as many primary carburetors as there are cylinder head ports, for example, three for a six-cylinder engine as disclosed. Each primary carburetor is provided by lfuel-mixture passage or mixing chamber into which there extends an upwardly projecting fuel nozzle 51provided'with a .metering orice 52, open at .its upper end and provided with small holes 53 adjacent the bottom of the passage 50. The fuel issues only from the holes 53 at idling and low speeds and light load; and above 10 `to 15 miles perl hour at light load for example, the fuel issues from the top ofthe nozzle 51. At idling or. lowv speed, light load, the depression at any nozzle 51 is insuilicient to lift the fuel through the outlet at the top of the nozzle, but does lift the fuel to a oint intermediate the orifices 53 and top o the nozzle which establishes a gravity head at the said orifices 53, and

entrances by relatively thin causes the fuel to flow therefrom under the influence of such gravity head. The three primary carburetor passages are arranged closely together in a horizontal row as shown in Figs. l2,` 13 and 14 so that they may be controlled by a simple throttle valve member or cylinder provided with notches 56 in alignment with the passages 50 respectively. The valve 55 is` held against endwise movement by a screw 57 engaging a groove 57a in the valve (seeFig. 16), and the valve has spindles 58 projecting therefrom for connecting it with controls to be described and supporting it for rotation.

The. passages 50 are separated at their artitions 59 which tend to prevent the inter erence of one carburetor with another.- The connection of the air inlets of the primary carburetors with the air chamber 42 tends to equalize the `distribution of fuel to the engine intake ports..

This connection is believed to eliminate eddies in the primary carburetors. The presence of eddies in the primary carburetors would interfere Ywith equal distribution since the eddies are not constant in effect but are erratic. This connection also tends to equalize the depression applied to all three carburetors, which mightotherwise be unequal due to differences in the length of the primary tubes.

Attention is here called to the fact that in the device disclosed herein allv the air passing through the primary carburetors passes the` fuel jets and in this respect the disclosed in the bottom wall of the chamber 42 in order to carry the liquid fuel to the engine for starting purposes. During engine operation most of t mitted to the chamber 42 from the main air y chamber 32; therefore it is ap arent that the sub-atmospheric pressure at t e fuel nozzles 5,1 will be substantially the same as kin the main air chamber 32, up to a certain engine speed which in this carburetor isa speed corres onding to a vehicular speed of 20-.25 mi es per hour on a level. At higher speeds the velocity head becomes effective on the pri- ,mary jets to form a super rich mixture, and is compensated for by opening the air valve 44 to admit additionalair vas later described..

The bottom' wall of the housing 30 supports a block -6 1 providing a distributing` canal or manifold 62 having an entrance at 63 and a plurality of outlets 64, one for each fuel nozzle'51. The block 61 in turn supports a fuel metering block 65 which projects downwardly into the ioat bowl and provides a pas,-

e air for the] primary carburetors is ad-4 sage 66 into which fuel is normally metered through an orifice 67 provided by a metering bushing 68. As fuel pas'sesupwardly to the passage 66 it must normally all pass through a metering orifice 69 in a flow operated valve 70, and thence past a check valve disc 71 normally resting upon 'a seat 72 and limited in its upward movement by stops73. Above certain engine speeds, the velocity of the flow of liquid through the passage 66 is suicient to ralse the flow control valve from its seat 74 so that fuel may flow also around the valve through passages V7 5, shown more particularly in Fig. 15, as well as through the metering passage 69. Under certain conditions, liquid fuel'may be admitted through the passage 66 also through a passage into which fuel may pass through a port' 81 when a valve 82 shown in Fig. 14 is lifted. The stem of the valve 82 terminates in a head l83 which i`s vertically slidable within a recess 84 provided `by the housing`30. -A spring 85 in this recess urges the valve 82 into closed position. The valve 82 is lifted by connections from the primary throttle 55 after a certain movement of the latter, such valve operating' connections being more fully described hereinafter.

The liquid fuel which is supplied to all of the primary carburetors ,through the holes 67 and 81 is contained in a fuel bowl 90 suspended from a frame 91 attachedby screws 92 to a flange 93 provided by the member 30. Liquid fuel is admitted to the bowl 90 through a passage 94 provided inthe frame 91 as shown in Fig. 6. .This passage has an enlarged screen chamber 95 containing a line mesh screen 96 supported by a fitting 97 having a tapped hole 98 for receiving afuel supply pipe. The screen 96 is retained against endwise move- -ment by a peg 100. The passage 94 communicates wit passages in t e valve seat member 101 provlding a seat v102 for a valve, 103 and having side outlet passages 104 through which fuel may ass when the valve 103 drops from its seat. he valve 103 is `pushed up- -yvardly against its seat by a lever 105 carrymg a float member 106. Lever 105 is pivotally mounted on a pin 107- supported by downwardly extending brackets 108 integral with the frame 91 and an extension 109 of the lever 105 limits counterclockwise movement 103 within the valve seat member 101 when .the float 106' falls.

The primary mixing chambers are .formed in what vmay be termed a distributor block A,

, which is cast integrally as part of the housing 30, said block `A projecting downwardl fromthe partition 40 as indicated lin Fi 1 Referring to Fig. 113, the center one o the primary mlxing-chambers 50 is in direct communication with a primary mixture tube 110 extending into the central branch 22 of the manifold 20 and each of the other carburetor passages 50 is provided within the bloclx A `of the lever and therefore retains the valve with a right angle bend leading into a pri# mary mixture plpe 111 having one end at-l tached to-the block A and the other end attachedto a flange 112 which is attached .by screws 113 as shown in Figs. 1, 4 andi5 to the air manifold at a point in alignment with one of its end branches 22. This connection places the outlet end of each pipe 111 in direct communication with a primary mixture pipe 110 extending through each `of the end branches 22 as shown in Fig. 5. Each engine intake port 23 provides ya secondary carburetor in which the primary mixture issuing from the pipe 110, may be mixed with air issuing from each branch Vof the air mani- Ifold. It has been' found advantageous to provide each engine intake port 23 with a ushing 114`providing a venturi passage-115.

VThis passage has been found to increase the velocity of the primary mixture flowing through the tube 110and therefore aids in acceleration of the engine. The venturi also assists in mixing the primary fuel mixture with the air in the secondary carburetor.v

Other iow accelerating means may be substituted for the venturi i'f desired. A

The operating connections for the primary throttle valve 55 and the air throttle valve 44 will now be described. It has been found desirable under part load conditions and for speed up to a certain amount, for example, to an engine speed corresponding to a vehicle speed of 20-25 milesper hour to supply all of the engine fuel mixture by the primary carburetors only and above such certain speed to gradually open the air'throttle 44 so that more air w1l1 be added to the primary mixture in the secondary carburetors in orderl that the fuel mixture will not become too rich during higher speeds. Accordingly, the

-throttles are so coordinated that the air throttle 44 will not be opened until the primary throttle has been opened to a certainl extent from its idling position shown in Fig.

r 11. As shown in Figs. 8 and 9, the primary throttle shaft 58 carries themain operating connects the stud 125 with an ear 129 at the upper end of the link 123. Two ears 130 integral with the link 123 and formed bypunching them from the main body of the link are provided with aligned tapped holes for receiving a screw 131 which may engage the stud 125.` In Fig. 8, the levers and 126 are in normal position corresponding respec- "tively to the idle position of the throttle 55 and the closed `position of the throttle 44 as shown in Fig. 11. The lever 120 is maintained 'in the desired. position by its connection with the control rod 120a. The spring 128 tends to move the lever 126 clockwise and hence maintains the valve 44 in closed position. When the lever 120 is moved counterwith a stop 132. As the lever 120 is moved clockwise "to closev the valve 55, the Valve 44 will bemoved into closed osition throu h the connection including t e link 123, t e spring 128 and the lever 126. After the valve 44 has been' closed the lever 120 may be moved 'm a clockwise direction until the screw 131 engages the stud Since the valve 44 cannot move any further in a clockwise direc- .tion from its closed position shown in Fig. 11,

the valve 55 cannot be moved any further into closed position afterthe screw 131 engages the stud 125. Therefore by turning the screw th-e idle position of the throttle 55 can be' adj usted.

Whenl the engine is running idle, the air throttle 44 will be closed, the primary valve 55 will bein idling position as shown in Fig. 11, andthe automatic air valve 33 will be slightly open. As the throttle 55 is opened to increase the speed of the engine, the depression in chamber 32 below the air valve will increase and the opening of the air valve f 33 will increase automatically to admit air to the primary carburetor so that the required engine power will be obtained. Below a certain engine speed'corresponding to a vehicle .speed of 20-25 miles er hour, for example,

air valve 44 will remain closed so that all of the engine fuel mixture vvll be supplied v through the primary mixture tubes 110 bythe primary car uretors. At a primary throttle position of' about 20--25 miles per hour vehicle speed on a level road for example, the air throttle 44 will begin to open'so that part of the airV admitted by the valve 33 will be supplied by the air manifold to thesecondi ary carburetor in order that the fuel mixture will not be too rlch for good performance -and economy when on part load at intermediate speeds.

As hasbeen stated previously, under engine operating conditions producing relatively high suction at the rimary noz'zlcs 51 and consequently relative y high velocity of the flow of fuel through the passage 66, the metering valve 70 will be lifted to permit the passage of a greater amount ofA fuel to the the stem of valve 82 distributing canal 62, Normally` this valve remains seated to keep the mixture lean below a certain medium speed, for example a vehicle speed of 30 miles per hour, when the vehicle is running on the level; or .under a certain lower speed under full load conditions.

A modified form of two stage metering Valve is shown in Figs. 18 and 19on which a valve 240 is shown, somewhat similar to valve 70. This valve rests on the seat 74and S provided with a meteringorilice 241 which is partially closed normally b a second flowcontrolled valve 242 guided by a bushing 243 held by a bracket 244 retained within the lvalve 240. The bracket 244 has notches 245 to permit the flow ofl fuel which passes through orifice 241, both before and after opening of valves 240. This construction may be used as a substitute for that shown in Fig. 14, when a fine degree of control of the'low of fuel through the passage 66 is desired.

yThe check valveI k.71'prevents the dropping of the column of liquid located above thelevel of the seat 72 in passage 66 down to the level ofthe fuel in bowl 90 when the engine speed is suddenly reduced producing a consequent reduction in depression at theV nozzles and velocity of fuel flow. Thus thevalve 71 prevents starving the engine for a period, so that the engine will operate smoothly upon a sudden reduction in speed.

When only'the primary throttle 55 is open all of the liquid fuel is'metered through the orifice 67 in order to keep the mixture lean for relatively low speed and light load operation or part throttle positions. Forl higher speed or greater load requiring the opening of the air throttle 44, it is desirable to meter more fuel into the 'passage 66. Therefore the valve 82 is caused to begin to lift as the valve 44 starts to open by means comprising a cam 140 attached to the shaft 58 and engageable with a levei` 141 having a notched ear 142 for receiving a portion of its shown in Figs. 10 and 14. The lever 141 is pivoted upon a screw '143 attached to a side wall of the housing 30.

The frame 91 and the fuel bowl 90 project laterally beyond this housing so that the valve 82 may extend directly downwardly into the fuel bowl. It isapparentfrom Fig.

7 that after the cam 140 has beenl moved in f a clockwise direction as viewed in Fig. 7 a certain amount corresponding to an opening movement of the valve as viewed 1n Fig. 11, the cam 140 will move the lever 141 ina clockwise direction asviewed in Fig. 7 in order to cause it to lift the valve 82. As the throttle 5 5 is moved toward closed posi-- tion, the cam 140 will move away from the lever 141 to permit thespring 85 to close the valve 82. The opening of this valve begins at about 20 miles per hour, vehicle speed, for

example, and continues during a considerable movement of the throttle. For example, the vehicle speed may be about 50 miles per hour when runnin lon a level road before the valve 8,2 is entlrely open.

The control of the air valve 33 for the pur-A pose of choking thecarburetor for p the engine when starting will now be de,-

scribed. The air valve 33 is 'supported by a valve ste'm -150- which is supported for vertical movement by a guide 151 screwed into the wall 40 of the housing 30 and extending at its lower end through a hole in the bottom wall of the chamber 42. The guide 151 ivspr)1 .Y

vided with, a shoulder 152 for limiting downward movement of a sleeve 153 whlch is slidable upon theexterior of the guide 151.

The spring 34 is located between the valve 33 ing 60 and a very rich mixture will be produced -due to the high depression `at the fuel nozzles 51. The sleeve 153 is moved upwardly by a bifurcated lever 155 carryin studs 156 which are received by the groove collar 154. The lever .155 is attached to a shaft 157 provided upon the exterior 'of the housing 30 with the lever arm 158 having a hole 159 for-receiving a carburetor choke rod 15911. T-he spring 34 will return' the lever 158'to'the position shown in' Fig. 4 against the end of an adjustable stop screw 160 after ythe choke rod 159a has beenreleased. The. stop screw 160 is screwed into a clamp bracket 161 integral with the part 36 and is clamped in any desired position of adjustment by a. clamp screw 162.

To prevent the. fluttering ofthe air valve 33 and to retard its movement toward o n positionfor purposes of acceleration, a ashpotY seat, the valve being provided by the bottom of the piston 171. A spring 176 confined between'the piston and a nut 177 screwed to the piston rod 172 tends to maintain the piston in contact with the valve seat 175. The hottom of the piston is provided with ports 178 communicating with an annular space 179 between the -bottom 'ofthe piston and the', flange 174. The piston 171 and the fl 174 provide a blow-off valve, the operation of which will be described later. The flange 174 is provided with ports 180 which may be Iclosed by a check valvev disc 181 which'is guided for vertical movement upon an extension 182 of the piston rod 172. The check valve disc 181 is held adjacent the iiange 174 by a washer 183 attached to the lower end of the-piston rod 172..

The lcylinder 170 is vertically slidable withina guide 184 integral with the frame 91. The guide 184 is provided with an aperture 185 and the cylinder 170 with an aperture 186 through which fuel from vthe fuel bowl 90 is admitted to the cylinder. The cylinder 170 is provided with a by-pass pipe 187 shown in Fig. 12 for the purpose of producin a va- -riable-retarding effect in accordance with the position'of the piston 171 relative to the cylinder 170. The by-pass pipe 187 is received by a notch `188 in the guide`184'and the cooperation of these parts prevents turning of the cylinder relative to the guide while permitting the guide to move vertically.

The cylincer 17 0 is provided adjacent its upper. end with a groove 190 which receivies lugs 191-carried b the arms of a bifurcated lever 192 mounte on a shaft 193. A lever l 194 shown in Fig. 7 is fixed to the shaft and carries an apertured lug 195 through which a rod 196 is slidable. One end-of the rod 196 is attached to a lever 197 loosely mounted on a shaft 19,3. The rod 196 carries adjustable nuts 198 and a sprin 199 is located between the nuts 198 and the ug 195. The spring 199 therefore urges the lug 195 against a stop shoulder 200 carried by the rod 196. Therefore by loosening a lock nut 201 and by turning the rod 196, the an ular 'relation of the levers 194 and 197 may e adjusted. By adspring 199 may be varied. The levei` 197-is provided with an arcuate slot 202 which receives a block '203 having a threaded' shank 203a (see Fig. 10a) which receives a nut 204 by which the block 203- may be clamped tothe lever 197 in various positions of ad justment relative to the slot-202. The block 203l provides a bearing for a pin 205e attached to a link 205 having its end 206 pivotally connected with a lever 207 pivoted `upon the screw 143. A cam 208, attached to the shaft 58, is engageable withthe lever 207. When the primary throttle A is opened, the shaft 58r will be turned in a clockwise direction as viewed in Fig. 7 to cause the lever 197 to move counterclockwise and to cause the lever 194 to move in the same direction through motion transmitted by the spring 199.` In Fig. 11, the shaft 193 will be moved clockwise to lift the cylinder 170. Due to y the mass to be lifted by the lever 197 motion is transmitted from it by the spring 199 whichwill vield in case of force suddenly applied 5 by the lever 197. The spring 199 therefore justing the nuts 198, the compression of the 'will protect the parts connected with the .lever 194 from undue strains.

Moreover, the provision of the'resilient lifting means for lifting the dashpot cylinder enables the lifting `movement toi take place throughout a greater period of time thanlif a positive lifting device were used. This will cause the opening movement of the air valve to be retarded for a longer time, thus roviding a richer mixture for acceleration or' a longer period.

While the engine is idling,; the air valve Y33 is opened b ut slightly because the depression in the chamber 32 is low.` If the throttles are opened, as when accelerating the vehicle, the depression increases, and the valve 33 tends to-open quickly but its motion is retarded by the dashpot since the check` valve 181 closes the holes 180 in the flange 174 (see Fig. 17), requiring the liquid in the cylinder 170 all to leak around the vpiston 171. This damping effect persistsrelatively undiminished until the by-pass 187 begins to be uncovered by the piston, during which interval, a richer mixturewill be supplied to the engine for purpose of acceleration. Because of the greater inertia of the fuel,vif the air valve were allowed to freely open on opening movements of the throttles, the increase in air flow would take place much more rapidly than the increase in fuel flow, which would 'result for a time inA a weakening of Vthe fuel mixture, until the effect of inertia was overcome. By retarding the o ening of the air valve this increase in air ow can be prevented and by retarding the valve opening sufficiently this weakening of the mixture can not only be prevented, but a mixture richer in the fuel content may be provided for purposes of ac- Celera-tion.

The damping gradually diminishes as the by-'pass 187 is being uncovered'to allow the valve 33 to open rapidly and supply air to the engine to give the required power as the fuelfiow and engine speed increase. The relation of the by-pass to the piston determines the duration of the valve-damping and this relation is varied automatically according tothe position of the primary 4throttle 115 55.' The greater the initial opening of the throttle 55 at the time it is suddenl opened further to accelerate,the less will be t e damping action. This variationy is present becauseless damping of the air valve would be required when moving from a 20 to a 25 miloper-hour throttle position than from a 10 Lo.- a 25 mile-per-hourposition, assuming that the grade ofthe road is substantially the same under both. conditions.

The sudden lifting of the dashpot cylinl der 17 0l also has a momentary retarding ef. fect upon Ithe opening'of the valve 33, by increasing the opposition to such opening movement because it tends to compress the 130 liquid in the cylinder and to lift the pistonl Therefore even though the piston were at the i point of opening the by-pass, this momentary retarding of the air valve 33 might take place under part throttle conditions.

One reason for the by-pass 187.jcan be explained by the following illustration. Suppose the vehicle is coasting at 40 miles per hour with the throttle closed, and the air valve 33 is nearly closed and then the throttles are opened suddenly to a position which Will cause the vehicle to attain a speed of 50 miles per hour on the level. The air valve 33 must quickly move from the idle to the 40 mile-per-hour position. This position requires considerable relative downward movement of the piston 171 in the' cylinder 170,

, and the piston should not be retarded unduly. Hence the by-pass 187 is required. There maybe some retarding of the air valve 33 before the by-pass is uncovered. Under certain operating conditions wherethe increase in depression below the air valve 33 to a certain high speed position.

is very sudden, itis not advisable to retard the opening. of the air valve. At such time the pressure upon the lliquid in the dashpot may be great enough to overcome the spring 176, whereupon the piston will be lifted from the flange 174 of the piston rod to permit escape of liquid through the holes 178 in the bottom ofthe piston. As soon as the pisjton separates from the fiange 174, it Wil remain separated until the pressure is relieved. This operation is knawn as the functioning of the blow-ofi' valve. Thus it is seen in the present example, the retarding of the air valve 33 may be relieved entirely if the throttles be very suddenly opened Under part load conditions and up to certanthrottle openings for producing vehicle speeds up to 20 to 25 miles per hour for example on a practically level road, the dashpot affords the only means for enriching the fuel-mixture for acceleration.' If it is d esired to accelerate to higher speeds, requiring a substantial opening of the air throttle 44, the rich mixture for acceleration is secured with the help of a suction controlleddevic'e to be described which injects fuel into the air intake just above the valve 33. The reasons for notl being able to obtain the acceleration mixture under all conditions wth the dashpot alone are the following.

First, although the primary fuel jets may admit sufiicient fuel to takel care of acceleration a material interval of time is required to move that fuel from the primary jets to the secondary carburetors. While the flow of air around the air valve is retarded when the opening of such valve is retarded, the air which does flow past such valve passes through the-main air passage to the secondary carburetors much more rapidly than the fuel mixture is moved through the primary tubes when the air throttle 44 is open. This air passingthrough the main air passage wouldform a lean mixture in the secondary carburetors momentarily at the instant following theopening of the valve 44 if it were for, acceleration purposes. The pump fur.-.

nishes a charge-of fuel lonly for an interval sufficient for primary acceleration fuel to pass from the primary jets to the secondary carburetors.

Second, when the valve 44 begins to open, at the 20u25 miles-per-hour position of the. primary throttle, for example the by-pass '187 is practically uncovered by the piston 171; and, therefore, the dashpot is practically ineffective toretard further opening movement of the air valve 33. Hence at speeds above that' atl'which valve 44 begins to open-the effect produced by retardation cf the opening movement of the air valve is l'oo negligible.

It is desired to call attention at this point to the fact that the manifold vacuum never drops low enough to cause the injector pump to operate when the secondary throttle 44 is closed. In other words, any acceleration from a low speed to any `speed under that at which the valve 44 begins to open is taken care of by the retardation .of the opening movement of the air valve, but when there is acceleration to any speed greater than that at which the opening movement of the valve 44 starts .both the air valve dashpot and the injector Vpump operate together to provide the necesasf herein the pump is operated only after the opening of the said secondary throttle', as has been set forth hereinbefore. The throttle passage 43 is connected by a passage 210 in the wall of the housing 30, a passage 211 in a bushing 212 and a hole 213 in a plate 214 with the interior of a metal bellows 215. The lower end of the bellows 215 is permanently attached to the plate 214 and the plate 214 is attached to the housing 30. The upper end v of the bellows 215 is closed by a disc 216 having a stem 217 which, by striking the bushing 212, limits the downward movement of the bellows 215. Its upward movement is limited' by a stop screw 218 adjustably supported by a housing 219 enclosing the bellows and cooperating with the plate 214 to provide a liquid fuel chamber surround-ing the bellows. Fuel is admitted to the fuel chamber 220 through a pipe 221 extending at its lower end below the level of fuel in the bowl 90 and provided at its upper end with a check valve 222. Fuel is delivered from the chamber 220 to the air inlet above the air valve 33 through a pipe 223 connected with acheck valve 224 and provided at its outlet with a plurality' of small holes 225 which operate as a spray nozzle. In Fig. 11, the check valves 222 and 224 are shown diagrammatically. In Fig. 3, the valve 222 is shown structurally. The housing 219 provides a passage 230connected with the pipe 221 and leading through a yvalve seat 231 upon whicha disc valve 232 is supported.V When the valve 232 is opened, fuel will pass-into the chamber 220 through a passage 233. The check valve 224'is shown structurally in Fig. 2. The housing 219 is provided with an opening 250 extending through a valve seat 251 closed by a valve 252. `When the valve 252 is open fuel may flow through the passage 25() into a passage'253 connected with the pipe 223. While the eugine is running under certain conditions with the throttle 44 closed or partly closed there will be a. depression at the passage 210 and hence within the metal bellows 215 thereby causing the bellows to move downwardly and increase the space in the chamber 220. At the same time fuel will be sucked through the pipe 221 to fill the chamber 220, the check valve 224 being closed. If the valve 44 be suddenly opened the depression at the passage 210 will immediately diminish permitting the bellows 215 to expand due to the operation of a spring 215a and decrease the space in the chamber 220 and force fuel past t e check valve 224, the check valve 222 then being closed. The fuel is preferably sprayed upon the air valve 33, because as this fuel is swept around the edge of the valve 33 it is broken up and mixes better with the air which it is intended to carburet. A small disc valve A210a in the Suction line 210 of the pump has a small opening therein and rests upon an annular seat 2101 in the housing 30 but may 211 in the bushing when the valve 210a strikes it. This construction provides for the ready expansion of the bellows to inject fuel when the depression at the passage 210 is relieved, and prevents pumping or squirtin of the fuel at low speed open -throttle position when the suction in the air manifold pulsates slowly, with the slow pump of the engine. The valve 210a also provides for a freer pumping l action.

Thus it is seen that in accelerating from'a low speed to any speed requiring the opening of4 both throttles, acceleration will be aided by the injector pump. When the present carburetor'is adjusted for acceleration from a coast of the vehicle, or for free engine acceleration, other conditions of-ac celeration are provided for. For example, in accelerating from five miles per hour to a vehicle speed corresponding to Wide open throttle position, the dashpot will retard the incoming air` for a brief period, or until the by-pass is uncovered during which time the injector pump suction chamber (within bellows 215) is under depression and is drawn downwardly and liquid fuel is received within the displacement chamber 220. After the by-pass is uncovered, the air valve will move quickly to its position corresponding to the wide open throttle position and vwill relieve the lvacuum in the pump suction chamber and allow the spring 215@ to expand the bellows and cause fuel to be injected into the air stream.

While the form of embodiment of the present invention as herein disclosed, constitutesy a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims Lwhich follow.

What is claimed is as follows:

1. In a charge forming device for an internal combustion engine, a mixing chamber, fuel andfair inlets therefor, a fuel supply chamber, a fuel conduit connecting the fuel supply chamber and said fuel inlet, and having a valve seat formed therein, a suction operated valve cooperating with said seat to control the flow of fuel through said conduit, a fuel metering orifice in said valve for controlli-ng the flow of fuel under certain operating conditions and a suction operated pin for controlling the area of said orifice.

2. In a charge forming device for an internal combustion engine, a mixing chamber, fuel and 'air inlets therefor, a fuel supply chamber, a fuel conduit connecting the fuel supply chamber and said fuel inlet, and havin'g a valve seat formed therein, a suction operated valve cooperating with'said seat to control the flow of fuel through the-conduit, said valve being relatively heavy so that the valve remains seated during low engine speed, a fuel metering orifice in said valve, a suction operated pin normally partially closing said orifice, said pin being relatively light, so as to enablepthe low ysuction affective at low'engine speed'to move said pin to its open position and permit an in- :reased flow of fuel through the valve.

3. Ina charge forming device for an inzernal combustion engine, a mixing chamber, fuel and air inlets therefor, a fuel supply zhamber, a fuel conduit connecting the fuel iupply chamber and said fuel inlet, a suc- ;ion operated compound valve in said conluit comprising an outer member controlling :he iiow of fuel at high speed, a metering )rifice in said member for controlling the flow )f fuel at low speed, and an-inner member normally partially closing such metering arice, said inner member Ymovable at low speeds to permit an increased flow of fuel shrough said metering orifice.

4. In a charge forming device for internal :ombustion engines having a plurality of intake ports, a main air manifold having branches communicating with said ports, a plurality of primary carburetors having outlets communicating with said branches, a separate fuel inlet for each primary carburetor, an air chamber having a valve controlled inlet, and a passage connecting said air chamber with all of said primary carburetors anterior to the fuel inlets therein whereby substantially air chamber pressure is communi- :ated to the primary carburetors, and the pressure in said carburetors is equalized.

5. In a charge forming device for an internal combustion engine having a mixing chamber therein, fuel and air inlets therefor, a primary throttle controlling the liow of fuel mixture therefrom, an air passage for admitting air to mix with the primary mixture, a throttle valve in said air passage, and a pump for injecting fuel to'enrlch the mixture, said pump being controlled by the suction in the air passage posterior to the throttle valve therein.

6. In a charge forming device for an internal combustion engine having a mixing chamber therein, fuel and air inlets therefor, a primary throttle controlling the ow of fuelmixture therefrom, an air passage for admitting air to mix with the primary mixture, a throttle valve in said air passage, a

suction operated pump for injecting fuel to enrich the mixture, anda suction passage communicating with the pump and said air passage at a point posterior to the throttle therein.

7. In a charge forming device for an internal combustlon engine having a mixing chamber therein, fuel and air inlets therefor, a primary throttle controlling the iiowof fuel mixture therefrom, an air passage for admitting air to mix with the primarymixture, a throttle valve in said a1r passage, and a suction operated fuel pump for injecting fuel to enrich the mixture, said pump comthe air passage posterior to the throttle therein. y

`8. In a charge forming device for an internal combustion engine having a mixing chamber therein, fuel and air inlets therefor, 'a' primary throttle controlling the iow of vfuel mixture therefrom, an air passage for admitting air to mix with the primary mixture, a throttle valve in said air passage, and a suction operated fuel pump for injecting fuel to enrich the mixture, said pump comprising a liquid chamber, a flexible bellows therein, and a suction passage connecting the interior of said bellows with the air passage at a point posterior to the throttle therein.

. l9. In a charge forming device for internal combustion engines having a mixing chamber, a fuel inlet therefor, a valve controlled air inlet, means for retarding the opening of the air valve to enrich the fuel mixture for acceleration at engine speeds up to a certain predetermined speed, a secondary air passage having a throttle therein, and means to enrich the fuel mixture for acceleration at higher speeds, said means comprising a fuel in]ecting pump controlled by the suction in said air passage posterior to the throttle valve therein.

10. In a charge forming device for internal combustion engines having a mixing chamber, a fuel inlet therefor, a valve controlled air inlet, means for retarding the opening of the air valve to' enrich the fuel mixture for acceleration at engine speeds u to a certain predetermined speed, a secon ary air passage having a throttle therein, means to enrich the fuel mixture for acceleration at higher speeds, said means comprising a fuel' injecting pump controlled by the suction in said air passage posterior to the throttle valve therein, and additional means for enriching the mixture at high speed.

11. In a charge forming device for internal combustion engines having a mixing chamber, a fuel inlet therefor, a valve concombustion` engines having a mixing chamber, a fuel inlet therefor, an air inlet, a valve controlling said 'inlet, a throttle controlling the outlet of said mixing chamber, an auxiliary air passage, al throttle valve therein, means for enriching the mixture on acceleration at low speed comprising a movable dashpot piston for retarding the opening movement of the air valve, means for enriching the mixture on acceleration at higher speeds comprising a movable cylinder associated with said piston, and means for moving said cylinder at such higher speeds, and additional means for enriching the mixture on acceleration at higher speeds comprising a suction operated fuel pump controlled by the suction in said air passage posterior to the throttle therein.

13. In a charge forming device for internal combustion engines having a mixing chamber, avfuel inlety therefor, an air inlet, a valve controlling said inlet, a throttle controlling the outlet of said mixing chamber, an auxiliary air passage, a throttle valve therein, means for enriching the mixture on acceleration at low s eed comprising a movable dashpot piston or retarding the opening movement of the air v a-lve, means for enriching. the mixture on acceleration at higher speeds comprising a movable cylinder associated with said piston, and means operated vby the primary throttle for moving said cylinder, at suchl higher speeds, and additional means for enriching the mixture on acceleration at higher speeds comprising a suction operated fuel pump controlled by the suction in said air passage posterior to the throttle therein.

14. In a charge forming device for internal combustion engines having a mixing chamber, a fuel inlet therefor, an air inlet, a valve controlling said inlet, a throttle controlling the outlet of said mixing chamber, an auxiliary air passage, a throttle valve therein, means for enriching the mixture on acceleration at low speed comprising a movable dashpot piston forretarding the opening movement of the air valve, means for enriching the mixture on acceleration at higher speeds comprising a movable cylinder associated with said piston, and means for moving said cylinder at such higher speeds, additional means for enriching the mixture on acceleration at higher speeds comprising a suction operated fuel pump controlled by the suction in said air' passage posterior to the throttle therein, and other additional means for enriching the mixture at high speeds.

15. In a charge forming device for internal combustion engines having a mixing chamber, a fuel inlet therefor, an air inlet, a valve controlling said inlet, a throttle controlling the outlet of said mixing chamber, an auxiliary .air passage, afthrottle valve therein,

means for enriching the mixture on accelera. tion at low speed comprising a movable dashpot piston for retarding the opening movement of the air valve, means for enriching the'mixture on acceleration at higher speeds comprising a movable cylinder associated with said piston, and means operated by the primary throttle for moving said cylinder at such higher speeds, additional means for enriching the mixture on acceleration at higher speeds comprising a suction operated l fuel pump controlled by the suction in said air passage posterior to the throttle therein, and further means for enriching the mixture at high speed comprising a fuel valve operl a plurality of secondary mixing chambers,

fuel inlets for supplying fuel to the primary mixture passages, a valve controlled air chamber, a passage connecting the air chamber With all the secondary mixing chambers, a passage conveying air from the air chamber to all of said primary mixture passages, said passage being so constructed that substantially the same suction is maintained in all of said primary mixture passages as in the air chamber. l

17. A charge forming device for an internal combustion engine comprising a plurality of primary mixture passages adapted to deliver a primary mixture of fuel and air to a plurality of secondary mixing chambers, fuel inlets for supplying fuel to the primary mixture passages, an air chamber, means for maintaimng a subatmospheric pressure in said air chamber, a passage connecting the air chamber with all the primary mixture passages anterior to the fuel nozzles, said passage being so constructed that substantially the suction is maintained in all of the rimary mixture passages adjacent the ucl inlets as is maintained in the air chamber.

18. A charge forming device for an internal combustion engine comprising a plurality of primary mixture passages adapted to deliver-a primary mixture of fuel and air to a lurality of seconder mixin chambers, fuel inlets for supplying uel to t e primary mixture passages, an air chamber, a spring closed, suction opened valve controlling admission of air to said air chamber, a passage connecting said air chamber vwith all of the mixture passages anterior to the fuel inlets, said passage being so designed that the air valve controls the suction in said air chamber and in said mixture passages adjacent the fuel inlets.

19. A charge forming device for internal combustion, engine comprising a plurality of primary mixing chambers from which a primary mixture of fuel and air is adapted to be conveyed to a plurality of secondary mixing chambers, fuel inlets supplying .fuel to said primary mixing chambers, an air chamber, a secondary air passage connecting the air chamber with all the secondary mixing chambers, anda primary air passage connecting i the air chamber with all of the primary mixing chambers, the area of the primary air passage relative to the total area of the outlets from the primary mixing chambers being such that substantially the same suction is maintained in all the primary mixing chambers as is maintained in the air chamber. 20. A charge forming device for internal combustion engine comprising a plurality of primary mixing chambers from which a primary mixture of fuel and air is adapted to be conveyed to a plurality of secondary mixing chambers, fuel inlets supplying fuel to said primary mixing chambers, `an air chamber, a ,5 secondary air passage connecting the air chamber with all the secondary mixing chambers, a primary air passage connecting the air chamber with all of the primary mixing chambers, and a valve in the secondary o air passage adapted to be opened at a predetermined engine speed, said primary air passage being sufficiently larger than the total area of the outlets from the primary mixing chambers, to enable substantially the :5 same suction to be maintained in said primary mixing chambers as in the air chamber up to said predetermined engine speed.

21. A charge forming device for internal combustion engine comprising a plurality of o primary mixing chambers from which a primary mixture of fuel and air is adapted t0 be conveyed to a plurality of secondary mixing chambers, fuel inlets supplying fuel to sald primary mixing chambers, an air cham- ;5 ber, a secondary air passage connecting the air chamber with all the secondary mixing chambers, a primary air passage connecting the air chamber with all of the primary mixing chambers, and a valve vin the secondary n air passage adapted to be opened at a pre-V determined engine speed, the size of the primary air passage relative to the total area of c the outlets from the primary mixing chambers being such that substantially the same f 5 suction is maintained in the primary mixing chambers as in the air chamber up to said predetermined engine speed, but a greater suction is maintained in the primary mixing chambers at speed higher than said prede- 0 termined speed.

In testimony whereof we hereto affix our signatures.

FRED E. ASELTINE. WILFORD H. TEETER 

